Mobile operators are today mainly using Wi-Fi to offload traffic from the mobile networks but the opportunity to improve end user experience regarding performance is also becoming more important. The current Wi-Fi deployments are mainly totally separate from mobile networks, and are to be seen as non-integrated. The usage of Wi-Fi is mainly driven due to the free and wide unlicensed spectrum, and the increased availability of Wi-Fi in mobile terminals like smartphones and tablets. The end users are also becoming more and more at ease with using Wi-Fi for example at offices and homes.
The different business segments for Wi-Fi regarding integration possibilities can be divided into mobile operator hosted/controlled vs. 3rd party hosted/controlled Wi-Fi Access Points (Aps) (here 3rd party is seen as anything else than mobile operator and that the 3rd party is not totally “trusted” by the mobile operator. 3rd party could be for example a Wi-Fi operator or an end-user him/herself.). In both segments there exist public/hotspot, enterprise and residential deployments.
Wi-Fi integration towards the mobile core network is emerging as a good way to improve the end user experience further. These solutions consist mainly of the components: common authentication between 3GPP (3rd Generation Partnership Project) and Wi-Fi, and integration of Wi-Fi user plane traffic to the mobile core network. The common authentication is based on automatic Subscriber Identity Module (SIM) based authentication in both access types. The Wi-Fi user plane integration provides the mobile operator the opportunity to provide the same services, like parental control and subscription based payment methods, for the end users when connected both via 3GPP and via Wi-Fi. Different solutions are standardized in 3GPP: Overlay solutions (S2b, S2c) are specified since 3GPP Rel-8 while integration solutions (S2a) are currently work-in-progress (S2a, S2b, S2c indicating the 3GPP interface/reference point name towards the PDN-gateway (GW)). These solutions are specified in 3GPP TS 23.402.
Most solutions of today require extensive signaling to a common authentication node, requiring resources and being a potential security risk.